Vehicle, energy conversion device and control method thereof

Abstract

The present disclosure relates to the technical field of vehicles, and provides a vehicle and an energy conversion device and a control method therefor. The energy conversion device includes a motor controller, a bus capacitor, a first switch module, a motor, and a second switch module. By controlling the first switch module and the second switch module to be turned on/off, a motor driving circuit can be formed by a battery pack, the first switch module, the bus capacitor, the motor controller, and the motor, and a charging and discharging circuit can be formed by the battery pack, the second switch module, the motor, the motor controller, and the bus capacitor.

What is claimed is: 
     
       1. A control method for an energy conversion device including a motor controller, wherein first ends of respective bridge arms of the motor controller are connected together to form a first bus terminal, and second ends of the respective bridge arms of the motor controller are connected together to form a second bus terminal; a bus capacitor, wherein a first end of the bus capacitor is connected with the first bus terminal, and a second end of the bus capacitor is connected with the second bus terminal and a negative electrode of a battery pack; a first switch module, connected between the bus capacitor and a positive electrode of the battery pack; a motor, having coils respectively connected with midpoints of the bridge arms of the motor controller; and a second switch module, connected between a neutral point of the coils of the motor and the positive electrode or the negative electrode of the battery pack, wherein the bridge arms of the motor controller includes upper and lower bridge arms configured to be turned on/off according to a duty cycle of a pulse width modulation (PWM) control signal to control a magnitude of a charging and discharging current of the battery pack, the method comprising:
 controlling the first switch module to be turned off and the second switch module to be turned on in response to receiving an instruction to enter a heating mode, to cause a battery pack, the second switch module, the motor, the motor controller, and the bus capacitor to form a closed charging and discharging circuit of the battery pack; and 
 controlling the first switch module to be turned on and the second switch module to be turned off in response to receiving an instruction to enter a driving mode, to cause the battery pack, the first switch module, the bus capacitor, the motor controller, and the motor to form a closed motor driving circuit, 
 wherein after entering the heating mode, the control method comprises: 
 controlling the motor controller to adjust a value of a current flowing through the charging and discharging circuit, to adjust an amount of heat generated by an internal resistance of the battery pack; 
 wherein before the controlling the motor controller to adjust a value of a current flowing through the charging and discharging circuit, the method further comprises: 
 acquiring a charging and discharging period of the battery pack and a target equivalent current value of the charging and discharging circuit; 
 acquiring a charging and discharging period of the charging and discharging circuit according to the charging and discharging period of the battery pack, and acquiring the duty cycle of the PWM control signal according to the target equivalent current value of the charging and discharging circuit; and 
 the controlling the motor controller to adjust a value of a current flowing through the charging and discharging circuit, to adjust an amount of heat generated by an internal resistance of the battery pack comprises: 
 controlling the upper and lower bridge arms of the motor controller to be turned on/off according to a charging period and a discharging period of the charging and discharging circuit and the duty cycle of the PWM control signal, to adjust the value of the current flowing through the charging and discharging circuit, so as to adjust the amount of the heat generated by the internal resistance of the battery pack. 
 
     
     
       2. The control method according to  claim 1 , wherein the acquiring the charging period and discharging period of the charging and discharging circuit according to the charging and discharging period of the battery pack comprises:
 configuring the charging and discharging period of the charging and discharging circuit as the charging and discharging period of the battery pack; and 
 the acquiring the duty cycle of the PWM control signal according to the target equivalent current value of the charging and discharging circuit comprises: 
 acquiring the duty cycle of the PWM control signal according to a pre-stored correspondence between the target equivalent current value and the duty cycle of the PWM control signal. 
 
     
     
       3. A control method for an energy conversion device including a motor controller, wherein first ends of respective bridge arms of the motor controller are connected together to form a first bus terminal, and second ends of the respective bridge arms of the motor controller are connected together to form a second bus terminal; a bus capacitor, wherein a first end of the bus capacitor is connected with the first bus terminal, and a second end of the bus capacitor is connected with the second bus terminal and a negative electrode of a battery pack; a first switch module, connected between the bus capacitor and a positive electrode of the battery pack; a motor, having coils respectively connected with midpoints of the bridge arms of the motor controller; and a second switch module, connected between a neutral point of the coils of the motor and the positive electrode or the negative electrode of the battery pack, wherein when the first switch module is turned on and the second switch module is turned off, a motor driving circuit is formed by the battery pack, the first switch module, the bus capacitor, the motor controller, and the motor; and when the first switch module is turned off and the second switch module is turned on, a charging and discharging circuit is formed by the battery pack, the second switch module, the motor, the motor controller, and the bus capacitor, the method comprising:
 controlling the first switch module to be turned off and the second switch module to be turned on in response to receiving an instruction to enter a heating mode, to cause a battery pack, the second switch module, the motor, the motor controller, and the bus capacitor to form the charging and discharging circuit of the battery pack; 
 acquiring the charging and discharging period of the battery pack and a target current waveform of the charging and discharging circuit in the charging and discharging period of the battery pack, wherein the charging and discharging period of the battery pack comprises a charging duration and a discharging duration; the charging duration comprises a plurality of charging periods of the charging and discharging circuit; the discharging duration comprises a plurality of discharging periods of the charging and discharging circuit; 
 acquiring a plurality of target equivalent current values corresponding to the target current waveform according to the target current waveform; 
 acquiring the duty cycle of the PWM control signal according to the target equivalent current value, and acquiring, according to the charging and discharging period of the battery pack and a number of the target equivalent current values, a number of the charging periods comprised in the charging duration and a number of the discharging periods comprised in the discharging duration, wherein one target equivalent current value corresponds to one charging period or one discharging period; 
 controlling the motor controller to adjust a value of a current flowing through the charging and discharging circuit, to adjust an amount of heat generated by an internal resistance of the battery pack; and 
 controlling the first switch module to be turned on and the second switch module to be turned off in response to receiving an instruction to enter a driving mode, to cause the battery pack, the first switch module, the bus capacitor, the motor controller, and the motor to form the motor driving circuit. 
 
     
     
       4. The control method according to  claim 3 , wherein the acquiring, according to the charging and discharging period of the battery pack and a number of the target equivalent current values, a number of the charging periods comprised in the charging duration and a number of the discharging periods comprised in the discharging duration comprises:
 the charging and discharging period of the battery pack, the number of the target equivalent current values, the charging duration, the discharging duration, the charging periods, the discharging periods, the number of the charging periods, and the number of the discharging periods satisfy the following formulas:
     T=T 1+ T 2; 
     T 1= N 1× t 1;
 
     T 2= N 2× t 2;
 
     N=N 1+ N 2; 
 
 T is the charging and discharging period of the battery pack; T1 is the charging duration; T2 is the discharging duration; t1 is the charging period of the charging and discharging circuit; N1 is the number of the charging periods; t2 is the discharging period of the charging and discharging circuit; N2 is the number of the discharging periods; and N is the number of the target equivalent current values. 
 
     
     
       5. The control method according to  claim 3 , wherein the acquiring a duty cycle of a PWM control signal according to the target equivalent current value of the charging and discharging circuit comprises:
 acquiring the duty cycle of the PWM control signal according to a pre-stored correspondence between the target equivalent current value and the duty cycle of the PWM control signal. 
 
     
     
       6. The control method according to  claim 5 , wherein the controlling the motor controller to adjust a value of a current flowing through the charging and discharging circuit, to adjust an amount of heat generated by an internal resistance of the battery pack comprises:
 controlling the upper and lower bridge arms of the motor controller to be turned on/off according to the charging periods of the charging and discharging circuit and the quantity thereof, the discharging periods of the charging and discharging circuit and the quantity thereof, and the duty cycle of the PWM control signal, to adjust the value of the current flowing through the charging and discharging circuit, so as to adjust the amount of the heat generated by the internal resistance of the battery pack. 
 
     
     
       7. The control method according to  claim 6 , wherein the controlling on/off of the upper and lower bridge arms of the motor controller according to the number of the charging periods, the number of the discharging periods, and the duty cycle of the PWM control signal, to adjust the value of the current flowing through the charging and discharging circuit comprises:
 acquiring the target equivalent current value corresponding to each charging period and the target equivalent current value corresponding to each discharging period and the duty cycle of the PWM control signal; and 
 controlling the upper and lower bridge arms of the motor controller to be turned on/off in each charging period and each discharging period according to the duty cycle of the PWM control signal, to adjust the value of the current flowing through the charging and discharging circuit to the target equivalent current value. 
 
     
     
       8. The control method according to  claim 7 , wherein after the controlling the upper and lower bridge arms of the motor controller to be turned on/off in each charging period and each discharging period according to the duty cycle of the PWM control signal, to adjust the value of the current flowing through the charging and discharging circuit to the target equivalent current value, the method further comprises:
 acquiring an actual current value in the charging and discharging circuit; acquiring a duty cycle correction value of a current charging period or a current discharging period according to a relationship between the actual current value and the target equivalent current value, and correcting a duty cycle of a next charging period or a next discharging period according to the duty cycle correction value.